1. Field of the Invention
This invention relates to loudspeaker systems and more particularly concerns an efficient speaker system having a wide dispersion pattern.
2. Description of Related Art
Despite widespread attempts over many years to improve electronics of reproduction of sound, none can be completely successful in the absence of satisfactory loudspeaker systems. Thus the intensive effort for development of electronic sound reproducing systems has been paralleled by comparable efforts for developing sound radiation systems, systems that can properly and realistically transduce the electrical signal received from an electronic amplifier into a radiated sound. In many sound radiating or loudspeaker systems it is highly desirable to radiate sound in a wide dispersion pattern. Speakers capable of radiating sound in a narrow dispersion pattern, patterns having a width on the order of 60.degree. or less, are widely available, but dispersion patterns of 120.degree. or more are difficult to attain with known systems. Some speaker systems having a wide dispersion pattern include an array of a number of speakers, each of which individually has a narrow dispersion pattern, but each of which is pointed in a different direction so as to collectively provide the wider pattern. Horns have been employed for providing a wide dispersion pattern, but these are limited either in frequency or by required physical size at certain frequencies.
Bearing in mind the cost, difficulties and other problems in speaker arrays or horn type arrangements, a variety of baffles or sound reflectors have been devised. Some reflective speaker systems are designed to reflect their radiated sound from walls or room corners to attain desired dispersion patterns. Other systems, such as that shown in U.S. Pat. No. 4,348,549, for example, attain a 360.degree. dispersion by directing speaker radiation vertically upwardly against the exterior surface of a conical reflector pointed downwardly toward the speaker and having its apex positioned at or about the plane of the speaker aperture. Such full cone reflectors are inefficient and introduce certain distortions in the form of interference. Because of the position of the full circular cone, a significant portion of the sound radiated by the speaker, which is radiated in an angular, although relatively narrow, pattern, is radiated in directions parallel to or past the reflective surfaces of the cone, and thus a part of the sound radiated by the speaker is projected upwardly toward the room ceiling, where it is lost or poorly or improperly reflected. Further, because of the position of the full circular cone, sound radiated from one side of the speaker in a direction generally parallel to the conical reflector surface may interfere with sound radiated directly vertically upwardly from the other side of the speaker and then reflected horizontally along a path intersecting the path of the direct radiated sound. This may cause interference and thus loss of certain sound components. Further, such conical reflectors provide for only a full 360.degree. dispersion and do not readily lend themselves to selective adjustment of dispersion pattern between angles of from 180.degree. to 360.degree.. Other straight, curved or elliptical reflectors fail to provide dispersion patterns of adequate width.
Accordingly, it is an object of the present invention to provide a speaker system having a wide dispersion pattern of a selected width which avoids or minimizes problems mentioned above.